Device for overcoming dead-centers



(No Model.)

S. T. SHORTESS.

DEVICE FOR OVERGOMING DEAD CENTERS. No. 331,914. Patented Dec. 8, 1885.

UNITED STATES PATENT @rrrcn.

STEPHEN T. SHORTES S, OF VINTON, IOWA.

DEVICE FOR OVERCOMlNG DEAD-CENTERS.

iiiiCIIE'ICATION fo.:ming part of Letters Patent No. 331,91, dated December 8, 1885.

Application filed September 26, 1985.

To all 10710721, it may concern.-

Be it known that I, STEPHEN T. Srroarnss, a citizen of the United States, residing at Vinton, in the county of Benton and State oflowa, have invented certain new and useful Iniprovements in Devices for Overcoming Dead- Centers; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to means for overcoming dead-centers in machinery driven by a rod or pitinan; and it particularly relates to that class in which the ordinary pitman is replaced by one of sufficient elasticity, and is so disposed between the crank and treadle, or its equivalent, that the crank at no time will be on a dead-center, either while in motion or at rest. Heretofore these elastic pitinen have been pivotally attached to the crank. and rigidly attached to the treadle. Thus the angle between the pitman and treadle remained relatively fixed, and as the efficiency of the pitnian to carry the crank past its dead-points depends upon the elasticity of the pitman, and this in turn upon the variation of said angle, prior devices were found objectionable, as they failed to provide any means for varying this angle; hence the object of this invention is to provide means for varying the angle between the pitman and treadle, or its equivalent, by shifting the position of the pitrnan to and from the axis about which the treadle vibrates; and to this end it consists in the details of construction, as more fully hereinafter set forth and specifically claimed.

In the accompanying drawings, Figure l is a side elevation of a portion of a stand providcd with a fly-wheel and treadle, the latter being shown in section, the parts being connected according to my improvement. Fig. 2 is a section on the line X X of Fig. 1, the stand being removed, and showing the preferred means of attachment between the treadle and the elastic rod. Fig. 3 is a rear edge View of a modified form. Fig. 4 is a detail perspec- Serial No. 178,290. (No model.)

tire view of the clip, showing the same in pa sition upon a portion of the trcadle-shaft with the elastic rod attached thereto.

The frame A, which may be of any wellknown construction, is simply shown as a means of support for the t1 y-wheel B, the treadle O, and the shaft D. The rod E, which is made of a suitable material possessing elastic properties, is connected to the treadle at its lower end in such a manner that if the other end of the rod were free it would, on operating the treadle, describe an arc of a circle of which the treadle-shaft would be the centerthat is to say, the connection between the rod and the treadle should be relatively fixed and not a pivotal one. The free end of the rod should be pivotally connected with the crank G on the shaft carrying the fly-wheel.

In disposing the parts it is best to have the rod E of such length and fastened to treadle at such an angle that the crank and treadle will normally rest in position off'their deadpoints.

By my invention the rod can be readily attached and detached, and the point of attachment between the rod and the treadle may be adjusted nearer to or farther from the treadleshaft,to regulate the tension or elastic force of the rod. The elastic rod E is bent near its lower end, and said portion 6 is passed through an eye or keeper, H, on the side of the treadle, and thence through the flanges t of a clip, I, surrounding the treadleshaft. The end of the bent part 6 is threaded for ashort distance, and nuts 11, mounted thereon one on either side of the flanges of the clip, serve to adjust the point of contact between the bent part of the rod and the eye attached to the treadle, besides causing the clip to bind around the shaftabout which the treadle oscillates.

From the foregoing it will be seen that the angle between the rod and its bent portion or treadle is only varied when the treadle is operated, and it is this variation in said angle which causes a manifest lateral straining of the rod, the rebound or recoil of which is utilized to carry the crank past its dead-point.

The dotted lines of Fig. 1 show the rod in position andjustin the act of passing the deadpoint, the rod being strained inward, as indicated by the arrow. The full lines show the portion of the rod after having passed the upper dead point, the arrow 2 indicating the direction of strain upon the red when the latter is carried past its lower dead-point.

As the working of the device depends upon the elasticity of the rod and the rigidness of its connection with the treadle or the shaft, in order that the operation of the treadle may cause a lateral straining of the rod, it has been found by practical demonstration to be immaterial whether the rod is used singly, as shown in Fig. 1, or in connection with an ordinary pit'man, as indicated in Figs. 2 and 3. It is manifest thata number of such rods,as E, may be employed, if found necessary, and also that the same may be attached at their lower ends to the opposite end of the treadles and on the opposite side of the support thereof, provided 5 the one shown in drawings.

and secured thereto by the threaded end of 5 said rod passing through its flanges, and nuts,

one on either side of the flanges, whereby the point of contact between the keeper and rod may be relatively changed or adj usted,substantially as and for the purpose set forth.

In testimony whereof I affix my signature in presence of two witnesses.

STEPHEN T. sHoRTEss.

WVitnesses:

W. P. VVHIPP E, H. E. VVARNER. 

